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/libavcodec/ppc/mpegvideo_altivec.c

http://github.com/FFmpeg/FFmpeg
C | 130 lines | 80 code | 16 blank | 34 comment | 15 complexity | 9f96e5bbc30f8d9cc1bf35fa7a9ee167 MD5 | raw file
  1/*
  2 * Copyright (c) 2002 Dieter Shirley
  3 *
  4 * dct_unquantize_h263_altivec:
  5 * Copyright (c) 2003 Romain Dolbeau <romain@dolbeau.org>
  6 *
  7 * This file is part of FFmpeg.
  8 *
  9 * FFmpeg is free software; you can redistribute it and/or
 10 * modify it under the terms of the GNU Lesser General Public
 11 * License as published by the Free Software Foundation; either
 12 * version 2.1 of the License, or (at your option) any later version.
 13 *
 14 * FFmpeg is distributed in the hope that it will be useful,
 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 17 * Lesser General Public License for more details.
 18 *
 19 * You should have received a copy of the GNU Lesser General Public
 20 * License along with FFmpeg; if not, write to the Free Software
 21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 22 */
 23
 24#include <stdlib.h>
 25#include <stdio.h>
 26
 27#include "config.h"
 28
 29#include "libavutil/attributes.h"
 30#include "libavutil/cpu.h"
 31#include "libavutil/ppc/cpu.h"
 32#include "libavutil/ppc/util_altivec.h"
 33
 34#include "libavcodec/mpegvideo.h"
 35
 36#if HAVE_ALTIVEC
 37
 38/* AltiVec version of dct_unquantize_h263
 39   this code assumes `block' is 16 bytes-aligned */
 40static void dct_unquantize_h263_altivec(MpegEncContext *s,
 41                                 int16_t *block, int n, int qscale)
 42{
 43    int i, level, qmul, qadd;
 44    int nCoeffs;
 45
 46    qadd = (qscale - 1) | 1;
 47    qmul = qscale << 1;
 48
 49    if (s->mb_intra) {
 50        if (!s->h263_aic) {
 51            if (n < 4)
 52                block[0] = block[0] * s->y_dc_scale;
 53            else
 54                block[0] = block[0] * s->c_dc_scale;
 55        }else
 56            qadd = 0;
 57        i = 1;
 58        nCoeffs= 63; //does not always use zigzag table
 59    } else {
 60        i = 0;
 61        av_assert2(s->block_last_index[n]>=0);
 62        nCoeffs= s->intra_scantable.raster_end[ s->block_last_index[n] ];
 63    }
 64
 65    {
 66        register const vector signed short vczero = (const vector signed short)vec_splat_s16(0);
 67        DECLARE_ALIGNED(16, short, qmul8) = qmul;
 68        DECLARE_ALIGNED(16, short, qadd8) = qadd;
 69        register vector signed short blockv, qmulv, qaddv, nqaddv, temp1;
 70        register vector bool short blockv_null, blockv_neg;
 71        register short backup_0 = block[0];
 72        register int j = 0;
 73
 74        qmulv = vec_splat((vec_s16)vec_lde(0, &qmul8), 0);
 75        qaddv = vec_splat((vec_s16)vec_lde(0, &qadd8), 0);
 76        nqaddv = vec_sub(vczero, qaddv);
 77
 78        // vectorize all the 16 bytes-aligned blocks
 79        // of 8 elements
 80        for(; (j + 7) <= nCoeffs ; j+=8) {
 81            blockv = vec_ld(j << 1, block);
 82            blockv_neg = vec_cmplt(blockv, vczero);
 83            blockv_null = vec_cmpeq(blockv, vczero);
 84            // choose between +qadd or -qadd as the third operand
 85            temp1 = vec_sel(qaddv, nqaddv, blockv_neg);
 86            // multiply & add (block{i,i+7} * qmul [+-] qadd)
 87            temp1 = vec_mladd(blockv, qmulv, temp1);
 88            // put 0 where block[{i,i+7} used to have 0
 89            blockv = vec_sel(temp1, blockv, blockv_null);
 90            vec_st(blockv, j << 1, block);
 91        }
 92
 93        // if nCoeffs isn't a multiple of 8, finish the job
 94        // using good old scalar units.
 95        // (we could do it using a truncated vector,
 96        // but I'm not sure it's worth the hassle)
 97        for(; j <= nCoeffs ; j++) {
 98            level = block[j];
 99            if (level) {
100                if (level < 0) {
101                    level = level * qmul - qadd;
102                } else {
103                    level = level * qmul + qadd;
104                }
105                block[j] = level;
106            }
107        }
108
109        if (i == 1) {
110            // cheat. this avoid special-casing the first iteration
111            block[0] = backup_0;
112        }
113    }
114}
115
116#endif /* HAVE_ALTIVEC */
117
118av_cold void ff_mpv_common_init_ppc(MpegEncContext *s)
119{
120#if HAVE_ALTIVEC
121    if (!PPC_ALTIVEC(av_get_cpu_flags()))
122        return;
123
124    if ((s->avctx->dct_algo == FF_DCT_AUTO) ||
125        (s->avctx->dct_algo == FF_DCT_ALTIVEC)) {
126        s->dct_unquantize_h263_intra = dct_unquantize_h263_altivec;
127        s->dct_unquantize_h263_inter = dct_unquantize_h263_altivec;
128    }
129#endif /* HAVE_ALTIVEC */
130}